<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>

    <style>
        body div:nth-child(1) {
            width: 200px;
            height: 200px;
            border: 5px solid gray;

            background: radial-gradient(red 50%, blue 50%, green);
            /* background: radial-gradient(red 25%, blue 50%, yellow); */

        }

        body div:nth-child(2) {
            width: 300px;
            height: 100px;
            border: 5px solid gray;
            margin-top: 10px;

            /* background: radial-gradient(circle, red, green); */
            /* background: radial-gradient(circle, red 50%, blue 50%, green); */
            background: -webkit-radial-gradient(0% 0%, farthest-corner, red, blue, green);
        }
    </style>
</head>

<body>
    <div></div>
    <div></div>
</body>

</html>